Carburetor



Jan. 2, M BUc kR CARBURETOR Filed Sept. 11, 1929 4 Sheets-Sheet 2 [77 renfor: Max flue/7e rer jy nmhilaiuf Att Jan. 2, 1934- M, BUCHERER 1,941,658

CARBURETOR Filed Sept. 11, 1929 4 Sheets-Sheet 3 1 5! 5 y 4 q H J 42 M I Inventor: Max Bucherer by' b Att Jan. 2,. 1934. v M. BUCHERER 4 Sheets-Sheet 4 ////AT////////////A III 1111:

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IT? ve H for: Max Buchefe'r" Patented Jan. 2, 1934 CARBUBETOB Max Bucherer, Berlin-Beinickendorf-West, Germany Application 391,928,

11 Claims.

thereby the amount of fuel delivered to the carburetor, in conformity with the position of the throttle, but I have found that this regulation is not nice enough for all fuels. It may be satisfactory for volatile fuels such as petrol and benzene but it is not adaptable enough for heavier fuels such as medium and heavy oil-for Diesel and other engines, as in these fuels the limits within which the composition of themixture may vary without deteriorating its properties-as to ignitability and complete combustion, are much narrower than in volatile fuels.

It is an object of my invention to provide means for regulating with absolute exactitude the proportioning of the mixture in conformity with the operating conditions at any moment and to this end I provide, in combination with the afore said means for varying the pressure conditions in the float chamber, mechanism operatively connected with such means for regulating the pressure exactly in conformity with operating conditions. t t

It will be understood that in this manner instead of the comparatively coarse regulation afforded by the throttle-controlled device aforesaid, I obtain a much more nice regulation which is necessary for heavy fuels but may also be useful for volatile fuels, such as petrol and the like, notwithstanding the fact that for these fuels it is not as important as for the heavy ones. For instance, when motor'cars have to stop atstreet crossings they will develop considerable quantities of dense smoke when restarting which is due to uncomplete combustion. By adapting my novel appliance the composition of the mixturewill be such as to obtain complete combustion under all conditions and therefore any smoke nuisance is eliminated.

My mechanism in its preferred embodiment comprises a cam shaped to the characteristic of a given fuel. For another fuel, a difierent cam is provided and in this manner by selecting the proper cam the carburetor may be adaptedto the conditions of any engine and to the properties of any fuel.

September 11, 1929, Serial and in Germany July 27,

It is another object of my invention to provide means for admitting secondary air with a view to still more exactly proportioning the composition of the mixture to given conditions, and to this end I provide an auxiliary throttle which cooperates with the main throttle and permits secondary air to enter the carburetor when the main throttle is closed. I may connect with this auxiliary throttle a calibrated fuel nozzle for exactly adapting the amount .of fuel to the amount of air admitted through the auxiliary throttle.

In the drawings afiixed to this specification and forming part thereof car uretors embodying my invention are illustrated ditically by way of example.

In the drawings Figs. 1 to 6 illustrate carburetors having closed iflbat chambers, the carburetor illustrated in Figs. 1' to 3 having separate main auxiliary throttles and the carburetor illustrated in Figs. 4 to 6 having combined throttles.

More particularly Fig. 1 is a partly sectional elevation of the carburetor, the section being taken on the vertical so 'axis of the float chamber,

Fig. 4 is a plan view of the carburetor, its main-throttle end broken away and parts omitted,

Fig. 5 is a section showing the upper portion of Fig. 1 drawn to a larger scale,

Fig. 6 is an axial section similar to the section in Fig. 2, but, as mentioned, showing a carburetor having combined throttles,

' Fig. '7 ma detailshowing a modified auxiliary throttle,

Fig. 8 is a section on the line 8-8 in Fig. 6,

Fig. 9 is a sectional view 9f a modified form of the invention showing the carburetor provided with a float chamber which is open to the atmosphere, and

Fig. 10 is a section on the line X-X in Fig. 6. m0 Referring now to the drawings and first to Figs. 1 to 5, 1 is the carburetor casing, 2 is an air nozzle in the casing, 8 is a pipe for supplying secondary air to the nozzle 2, 4 is a closed fioat chamber, 64 is its lid, 5 ma passage'having a horizontal and a vertical branch as best seen in Fig. 5. The horizontal branch of the passage opens'into the float chamber 4 just below its lid 84 and the vertical branch is connected to a pipe 38 which extends to a short distance above the I nozzle 2 so that the passage 5 connects the space in the casing 1 to the space above the fuel in the carburetor. The pipe 38 may also open into the air space of the nozzle. 6 is the main throttle, '7 is a control shaft, 8 is a cam on the control shaft for operating the throttle, and 9 is the closing spring of the throttle.

10 is an air inlet valve in a chamber 14 of the carburetor casing, 11 is a hollow air inlet plug, 13 is a screen in the plug, 12 is a passage extending from the chamber of the inlet valve 10 to the float chamber 4, and 15, 16 are spindles at either end of the valve 10, the spindle being threaded at its upper end and connected with a nut 1'7 having a detent 19. is a plug closing the chamber of the valve 10, and 18 is a closing spring inserted between the plug 20 and the valve 10. It will be understood that the nut 1'7 partakes in the movement of the valve 10 and in order to permit this, the plug 20 is provided with serrations on its perimeter and the detent 19 is adapted to slide in the serrations. By means of the nut 1'7 the valve 10 is adjusted by hand so as to keep it permanently open for a given amount or to regulate the quantity of fuel temporarily.

21 is a cam as shown in Fig. 3 which is secured on the throttle control shaft '7 and stepped in conformity with the required exact regulation aforesaid, and 27 is a liner which is secured to the lower end of the spindle 16 and held in contact with the cam 21 by the spring 18. Obviously, the liner 2'7 may be dispensed with but it is preferably provided as various positions of the valve may be obtained with a single cam 21 of a given ch'aracteristic,. while without the liner the cam would have to* be exchanged for each position of the valve'with respect to the cam.

22, 22 are two rotary slide valves on the outer end of the control shaft '7, and 23 are passages connected with the secondary air pipe 3 and controlled by the valves 22.

Fuel from the float chamber 4 is admitted to a chamber 29 of a hollow lug 30 which is cast to the lower part of the casing 1. 31 is a plate having a calibrated bore 32 and 33 is a counterplate both secured in a female thread in the chamber 29. 34 is a tubular insertion which is held by the plates 31, 33 and projects into the air nozzie 2 with its upper end, and 35, 36

and 37 are jet-pipes of various lengths inserted at this end of the tube 34 and adapted to inject fuel into the nozzle 2, the three Jet-pipes being arranged in line with the end of the secondary air pipe 3, as shown in Fig. 2.

The passage 5 opens into the float'chamber 4 at the same level as the air inlet passage 12. The passage 5 has been shown at a slightly higher level in Figs. 1 and 5 for the sake of clearness. 39 is a choke tube secured in the casing 1 for cooperation with the nozzle 2, and 40 are bores in the nozzle through which the air flowing past the nozzle 2 draws fuel from the jet pipes 35, 36 and 37, which is atomized in the choke tube 39. On account of the various lengths of the jet-pipes 35, 36, 3'7, the amount of fuel delivered per unit of time is a function of the fuel level in the tubular insertion 34.

Any suitable means such as an arm 41 may be provided for rotating the control shaft '7.

Upon rotation of the shaft the secondary air valves 22 lay open a certain percentage of the end of the shaft '7 is displaced causing the inlet valve 10 to assume such a position as to admit into the float chamber a quantity of air which is exactly regulated in conformity with the position of the main throttle 6 or the auxiliary throttle constituted by the valves 22, into the float chamber 4. When the valve 10 is closed the pressures in the float chamber and the carburetor are equalized through the passage 5 and its connecting pipe 38.

The vacuum in the carburetor casing 1 is a function of the lift of the main throttle 6, being inversely, proportional to the opening of the throttle. The velocity of the flow in the carburetor and in the secondary pipe 3 increases with the vacuum. When the main throttle 6 is opened further in order to increase the power output of the engine the vacuum in the casing is reduced in proportion and this would also reduce the amount of fuel delivered by the pipes 35, 36, and 37. This, however, is prevented by the cam 21 which is so shaped as to open the air inlet valve 10 wider with increasing lift of the throttle 6. This increases the pressure in the float chamber 4 as more air is admitted through the passage 11, the fuel level rises in the tubular insertion 34 and the shorter jet-pipes 35 and 37 par take in the delivery of fuel.

Referring now to Figs. 6 and 10, these illustrate a modifled nozzle 2. The nozzle has a cavity 61 which is connected to the bores 40, and 62 is a passage connecting the cavity 61 to the tubular insertion 34.

Figs. 6, 7 and 8 illustrate an auxiliary throttle inserted in the main throttle 6 instead of the rotary valves 22 described which have a tendency to leak. 42 is an extension of the secondary air pipe 3 and 43, Fig. 6, is an auxiliary throttle at the end of the extension and seated in the main throttle 6, 44 being its seating spring. 45 is a boss on the control shaft '7, 46, 46 are eccentrics at either end of the boss, 49 is a square sleeve on the extension 42, and 4'7, 48 are flanges on the sleeve adapted to be engaged by the eccentrics 46, 46. 50 is a tubular boss on the main throttle 6 to which the extension 42 is fitted to slide, 51 is a guide for the boss 50, 52 is the valve seat of the main throttle 6 to which the guide 51 is connected by ribs, and 53 are perforations in the extension 42 near the auxiliary throttle 43.

When the engine is started the control shaft '7 lifts the auxiliary throttle 43 from its seat in the main throttle 6 and air flows past the seat of the auxiliary throttle to theperforations 53, through the extension 42 and through the secondary pipe to the air nozzle 2, as described, where suction is exerted on the fuel. Upon further rotation of the shaft '1 the flange 48 engages the boss 50, opening the main throttle 6.

Referring now to Fig. '7 this shows a check 54 at the end of the insertion 42 instead of the valve 43 which limits the stroke of the insertion 42 with respect to the main throttle 6', and 55 are perforations in the insertion 42 which' are laid open to a greater or lesser extent by displacing the insertion 42, admitting corresponding quantities of secondary air per unit of time. In the type of auxiliary valves described with reference to Fig. 6, the perforations 53 only acted as passages while in the present instance they meter the percentage of secondary air. The type illustrated in Fig. '7 is more simple than that illustrated in Fig. 6 as it does not require an exactly ground valve seat in the main throttle 6 and is therefore provided principally for carburetors of smaller and cheaper types.

Referring now to Fig. 9, the float chamber is under atmospheric pressure through the medium of any suitable passage such as a hole in its cover, not shown. The passage 12 and the valve 10 are designed and operated in the same manner as described with reference to previous figures, but the passage 5, 38 between the float chamber 4 and the carburetor casing 1 is dispensed with, and a passage 25 is provided instead extending from the casing of the carburetor to the chamber 26 of the valve 10. The function of the valve 10 is not that of an air inlet valve but only that of a control valve for the passage 25.

In the example illustrated the main throttle 62 is not arranged at the inlet of the carburetor as the throttle 6 described with reference to previous figures, but in a pipe 63 between the engine, not shown, and the carburetor. Any suitable mechanism, not shown, may be provided for connecting the main throttle 62 with the control shaft '7- on which the valves 22 constituting the auxiliary throttle are arranged as described.

Without the control valve 10 the fuel supply would become excessive when the vacuum in the carburetor increases with increasing load but this is prevented by opening the control valve 10 to an increasing extent through the medium of the cam 21. In proportion to the lift of the valve 10 a corresponding percentage of the air flowing to the float chamber from the atmosphere is drawn into the carburetor through passages 12 and 25 and the supply of fuel is reduced in proportion.

I am not limited to carburetors in which the fuel is delivered by suction but my invention may also be applied to carburetors of the jet-type in which the fuel is supplied under pressure.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

In the claims affixed to this specification no selection of anyparticular modification of the invention is intended to the exclusion of other modiflcations thereof and the right to subsequently make claim to any modification not covered by these claims is expressly reserved.

1. A carburetor comprising a casing, a main throttle adapted to admit primary air to said casing, a shaft in said casing, a stem adapted to be displaced in said casing, means operatively c ,nnecting said shaft and said stem, an auxiliary throttle on said stem, and means on said stem for operating said main throttle.

2. A carburetor comprising a casing, a fuel nozzle in said casing,'a main throttle adapted to admit primary air to said casing, a hollow stem in said casing connected with said nozzle, means for displacing said stem with respect to saidnozv zle, an auxiliary throttle on said stem, and means for admitting air to said stem through said auxiliary throttle.

3. A carburetor comprising a casing, a fuel nozzle in said casing, a main throttle adapted to admit primary air to said casing, a hollow stem in said casing connected with said nozzle, means for displacing said stem with respect to said nozzle, an auxiliary throttle on said stem, and a seat for said auxiliary throttle in said main throttle, said stem having perforations adapted to admit air from said seat into said stem.

4. A carburetor comprising a casing, a fuel nozzle in said casing, a, main throttle adapted to admit primary air to said casing, a hollow stem in said casing connected with said nozzle, means for displacing said stem with respect to said nozzle, said stem having perforations adapted to be controlled by relative displacement of said main throttle and said stem.

5. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a float chamber, and means for regulating the pressure above the liquid level in said chamber operatively connected with said throttle, said means including an adjusting instrumentality having its design graduated according to the specific fuel characteristics of a given fuel to be used with said carburetor, whereby to regulate the pressure above said liquid level according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which said carburetor is applied.

6. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a closed float chamber, an air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float cham-' ber comprising passages connecting the space above the liquid level in said float chamber with the interior of said casing and to atmosphere, a valve in one of said passages, and means operatively connected to the said valve and throttle graduated according to the specific fuel characteristics of a given fuel to be used with said carburetor and adapted to regulate the position of said valve according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which the carburetor is applied.

'1. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a closed float chambenan air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float chamber comprising passages connecting the no space above the liquid level in said float chamber with the interior of said casing and to atmosphere, a valve in one of said passages, and manually controlled means operatively connected to the said valve and throttle graduated according to the specific fuel characteristics of a given fuel to be used with said carburetor and adapted to regulate the position of said valve according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which the carburetor is applied.

8. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a closed float chamber, an air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float chamber comprising passages connecting the space above the liquid level in said float chamber with the interior of said casing and to atmosphere, a valve in one of said passages, a seating spring .associated with said valve, and manually controlled means operatively connected to the said operating conditions of the engine to which the carburetor is applied.

9. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a float chamber, an air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float chamber comprising a passage connecting the space above the liquid level in said float chamber with the interior of the carburetor casing, a valve in said passage, and means operatively connected to the said valve and throttle, said last mentioned means having its design graduated according to the specific fuel characteristics of a given fuel to be used with said carburetor and adapted to regulate the position of said valve according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which the carburetor is applied.

10. A carburetor comprising a casing, a throttle for controlling the flow of combustion air in said casing, a closed float chamber, an air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float chamber comprising passages connecting the space above the liquid level in said float chamher with the interior of said carburetor casing and to atmosphere, a valve in one of said passages, and manually controlled means operatively connected to the said valve and throttle graduated according to the specific fuel characteristics of a given fuel to be used with said carburetor and adapted to regulate the position .of said valve according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which the carburetor is applied.

11. A carburetor comprising a casing, a throttle for controlling the flow of combustion air, in said casing, a float chamber, an air and fuel nozzle in said casing supplied with fuel from said float chamber, and means for regulating the pressure above the liquid level in said float chamber comprising a passage connecting the space above the liquid level with the interior of the carburetor, a valve in said passage, and a cam operatively connected to said throttle and arranged to act upon 'said valve so as to regulate its position according to the fuel requirements for complete combustion at any given throttle position under the various operating conditions of the engine to which the carburetor is applied, said cam being graduated to accord with the specific fuel characteristics of a given fuel to be used with said carburetor.

MAX BUCHERER. 

